Increased Storage Capacity Research Articles

Alterations of a CaCl2 Alginate Composite for Thermochemical Heat Storage during the Hydration in a 1 L Packed Bed Laboratory Reactor

A composite material of alginate and CaCl2 was tested in a laboratory reactor (1 L) for its ability to thermochemically store heat. The material was exposed to air at 25 °C and 25% RH to prevent the salt from dissolving, and the heat evolution was observed over a period of 15 cycles. To evaluate the changes in the material, samples were taken after 5, 10 and 15 cycles and the material properties and calorimetric characteristics were examined. A change of the material in favor of the heat release was determined, so that an increase of the heat storage capacity from 1.28 kJ∙cm−3 to 2.11 kJ∙cm−3 was detected, with a simultaneous steep decrease of the pore volume in the range from 0.01 to 10 μm. The temperature lift of the reactor showed a significant increase, with the first cycle showing the smallest amount.

Experimental and numerical investigations on operation characteristics of seasonal borehole underground thermal energy storage

To investigate operation characteristics of seasonal borehole underground thermal energy storage (SBUTES) with different operational strategies, a model test platform with reduced size was established based on similarity principle. The test results show that the larger the start-stop time ratio, the smaller the average heat exchange rate per unit depth (HERPUD) of borehole, and the lower the energy storage efficiency, but the thermal energy storage and extraction capacity increase. For the time ratio of thermal energy storage to extraction (TROSE), the larger the TROSE, the larger the thermal imbalance rate of energy storage body, which will lead to the gradual increase or decrease of temperature of energy storage body and is not conducive to the operation of energy storage. Compared with the asynchronous mode of storage and extraction, the synchronous mode of storage and extraction can effectively reduce the average temperature of energy storage body and increase the heat exchange efficiency of boreholes during the thermal energy storage. The focused energy storage mode can improve the energy storage efficiency and soil temperature recovery rate, balance the thermal energy storage and extraction capacity, and thus the performance of SBUTES can be optimized. A 3-D CFD model of borehole energy storage was established to further find the influences of borehole layout forms, layout spacing and depths on characteristics of the SBUTES. It can be found that for the energy storage efficiency, the hexagonal layout is the highest, the rectangular layout is the lowest, and the circular layout is slightly higher than the square one. Under the same volume of boreholes group, increasing the spacing of inner boreholes can effectively alleviate thermal interference of inner boreholes during the thermal energy storage, and the heat exchange capacity undertaken by inner boreholes can be improved. But it is not conducive to thermal energy extraction. Although increasing borehole depth can increase thermal energy storage and extraction capacity and system operation efficiency, the increase degree is decreasing with the increase of borehole depth, and the greater the borehole depth, the smaller the influence of borehole depth on characteristics of SBUTES.

Synthesis and Characterization of Doped Magnesium Hydroxide for Medium Heat Storage Application.

The amount of waste heat generated annually in the UK exceeds the total annual electricity demand. Hence, it is crucial to effectively harness all available sources of waste heat based on their varying temperatures. Through suitable technologies, a substantial portion of this waste heat has the potential to be recovered for reutilization. Thermochemical energy storage (TCES) provides the best opportunities to recover waste heat at various temperatures for long-term storage and application. The potential of TCES with magnesium hydroxide, Mg(OH)2, has been established, but it has a relatively high dehydration temperature, thus limiting its potential for medium-temperature heat storage applications, which account for a vast proportion of industrial waste heat. To this end, samples of doped Mg(OH)2 with varying proportions (5, 10, 15, and 20 wt%) of potassium nitrate (KNO3) have been developed and characterized for evaluation. The results showed that the Mg(OH)2 sample with 5 wt% KNO3 achieved the best outcome and was able to lower the dehydration temperature of the pure Mg(OH)2 from about 317 °C to 293 °C with an increase in the energy storage capacity from 1246 J/g to 1317 J/g. It also showed a monodisperse surface topology and thermal stability in the non-isothermal test conducted on the sample and therefore appears to have the potential for medium heat storage applications ranging from 293 °C to 400 °C.

An elephant in the room—EU policy gaps in the regulation of moderating illegal sexual content on video-sharing platforms

Abstract With the availability of broadband internet and a significant increase in storage capacity, people are sharing a dynamically growing amount of multimedia content on video-sharing platforms, including sexually explicit content. While sexual content on the internet is not illegal per se and remains in the domain of economic services, there are certain forms of sexually explicit content that are criminally unlawful, such as child pornography or non-consensual pornography. This article explores why the current business-oriented regulatory environment fails to provide effective tools to combat illegal sexual content: first, from the perspective of content moderation on video-sharing platforms, and then from the perspective of substantive criminal law. After mapping the gaps in policy at all levels of content regulation, the article offers recommendations to address these issues, open up a policy debate and influence policy makers.

Reservoir inventory for China in 2016 and 2021

Reservoir inventories are essential for investigating the impact of climate change and anthropogenic activities on water scape changes. They provide fundamental data sources to explore the sustainability and management efficiency of water resources. However, publicly released reservoir inventories are currently limited to a single temporal domain. As a result, the effectiveness of governmental policy implementation on water resources remains to be explored due to the lack of multi-time datasets. In this study, we generated a reservoir inventory for China for the years 2016 and 2021 with an overall accuracy of 99.71%. The reservoirs were visually interpreted from annually composited Landsat images, and each reservoir is represented by a polygon with attributes of reservoir name, area and storage capacity. About 10.32% of the reservoirs have increased storage capacity from 2016 to 2021, while 22.73% have decreased. Most provinces and river basins in China have expanded their accumulated storage capacity from 2016 to 2021.

Experimental analysis of energy storage performance of phase change materials in horizontal double-glazing applications

In this study, phase change material (PCM) energy storage performance was experimentally investigated for horizontal double-glazing applications. In this context, it was aimed to use PCM for energy storage in horizontal insulating glass applications, and optimize amount of PCM in the glass and the effect of the surface area it occupies on the indoor light level were analyzed. In this regard, the temperature variation in the glass with the amount of PCM was observed and the optimum amount of PCM was evaluated. The experiments were carried out on an insulated test cabin using double-glazed test elements with different PCM ratios as 0 %, 15 %, 30 %, 45 %, and 100 %. An external light source was used to create constant radiation conditions during the experiments and temperature measurements, thermal camera images, as well as light intensity measurements were taken in the test cabin. The results revealed that the increase in the energy storage capacity with the amount of PCM is limited, while the light transmittance decreases continuously due to the solid PCM shading. In other words, as the amount of used PCM increases, the energy storage capacity increases and thermal comfort conditions improve. However, this increase stopped at a certain point and a constant trend was observed. It was concluded that, this situation occurs due to the blocking of the radiation entering the indoor environment and the decrease in the radiation intensity. For the 30 % area ratio, the cooling period was extended by 450 min compared to the reference case, and longer thermal comfort conditions were provided.

Lightweight Read Reference Voltage Calibration Strategy for Improving 3-D TLC NAND Flash Memory Reliability

Flash memory has gradually become the dominant storage device in the consumer market and data centers since the storage capacity increases and production costs decline. Unfortunately, as the bit density of flash memory increased, the severity of reliability issues has escalated. Read retry is necessary to recover high bit-error-rate flash data; however, read retry requires the flash to perform sequential read operations, which significantly increases read latency. To improve the flash memory read performance, a reliable adaptive optimization strategy for flash memory read reference voltage (RRV) is urgently needed. In this paper, we performed a full range of error characterization tests on three-dimensional (3-D) triple-level cell (TLC) flash memory, focusing on the effects of retention leakage, P/E wear, and interlayer variation on the threshold voltage. Finally, a lightweight flash memory RRV calibration strategy was constructed. The experiment results show that the predicted RRV using the proposed strategy is very close to the actual optimal RRV, reducing the raw bit error rate (RBER) of the same model of flash memory by up to 93.2%.

Natural convection and structural impact of rectangular PCM storage units through the modular expansion

To increase the storage capacity and air flow rate of the rectangular thermal energy storage unit (RTESU) for enhancing its application capability, three modular units with air flow rates of 60 m3/h, 120 m3/h, and 180 m3/h for heights of 150 mm, 300 mm, and 450 mm are proposed. Besides, the effect of natural convection (NC) on the charging and discharging process is examined during the modular expansion of the RTESU. The melting performance including melting duration and phase change process is numerically investigated by varying the configurations such as module configuration, non-uniform, and eccentric tube arrangements. The results show that NC has a significant impact on the charging process. It is further demonstrated that the charging process can be enhanced by about 14.58 % and 13.61 % when non-uniform and eccentric tube arrangements are implemented, respectively, as they both increase the area dominated by NC. However, the non-uniform tube arrangement for acceleration of the melting process is gradually enhanced with the increase in storage unit height compared to that of the eccentric tube arrangement. It is worth noting that the Nusselt number (Nu) is introduced for examining heat transfer performance during the melting process with different unit configurations. And the correlation between the dimensionless numbers is applied to predict the liquid fraction for different configurations. For the heat release process, the performance including air outlet temperature, heat extraction, and heat release efficiency of the modular RTESU is evaluated. It is found that the NC has a negligible effect on the discharging process, which is dominated by heat conduction. With the modular expansion, an increase in air flow rate and heat storage capacity as well as the maintenance of a higher heat release efficiency of about 84.97 % can be achieved in the RTESU.

Phase distributions in YB3 alloys (B[dbnd]Cr, Mn, Fe, Co, Ni, Cu) and related hydrogen storage performances

The phase distributions and hydrogen absorption and desorption performances for YB3-type alloys were investigated in the paper. The compositions of the alloys can be generally divided into three categories, and the pure metal phase will disappear gradually with the increase of B-side atomic number in the YB3 alloys. The hydrogen storage capacity and desorption rate increase first, and then decrease with the atomic number. The dehydrogenation temperatures and the molar enthalpies of the hydrides during the desorption process are also discussed.

АКУМУЛЯТОРИ ТЕПЛОВОЇ ЕНЕРГІЇ

The article provides an analytical review of thermal energy storage. The reasons determining their demand are shown. It has been established that the market of thermal accumulators is developing quite dynamically. According to the forecast of the International Renewable Energy Agency, the global market for thermal accumulators may triple by 2030 from 234 GWh of installed capacity in 2019 to about 800 GWh in 2030. Investments in the development of thermal accumulators are expected to reach 13–28 billion US dollars. Their capacity for power generation can be 491–631 GWh, for heat supply – 143–199 GWh, for cooling – 23–26 GWh. Bloomberg NEF considers the main drivers of such a sharp increase in energy storage capacity are the US Inflation Reduction Act, which provides for more than $369 billion in financing for clean technologies, as well as the European Union's RE Power EU plan to reduce dependence on gas from Russia. The significant additional storage capacity expected from 2025 in the utility sector is in line with the very ambitious renewable energy targets set out in the REPowerEU plan. The purpose of this review is the search and analysis of thermal energy storage technologies for their possible use in the centralized heat supply of Ukraine. The conducted review showed that the most advanced technology for the accumulation of thermal energy is heat capacity of the material storage. It is the cheapest and most common in centralized heat supply. For short-term storage of heat energy, it is advisable to use storage tanks and main heat networks. Special insulated concrete underground storages of both natural and artificial origin are used for seasonal accumulation of thermal energy. A promising technology for seasonal thermal energy storage is an ice battery developed by the Viessmann company, which requires much less space than the heat capacity of the material storage technology. Thermochemical batteries are in the early stages of development, their demonstration samples may be manufactured by 2050. Keywords: battery, thermal energy, heat capacity, phase transition.

New concept of renewable energy priority zones for efficient onshore wind and solar expansion

The intensification of climate change impacts requires a fast and efficient transition of energy systems and deployment of renewable energies worldwide. An adequate site assessment strategy forms the basis for expanding installed capacities and energy yield. This study applies a set of meaningful criteria to determine site suitability for Germany's onshore wind and utility-scale solar photovoltaics facilities. An aggregated priority index involving meteorological-technical, economic, and environmental criteria is developed and used in a new concept for identifying renewable energy priority zones, where installations of wind and solar energy facilities should be prioritized. As a novelty, this resource-centered approach does not only analyze the mean energy potential as a meteorological criterion but also accounts for other characteristics such as variability, complementarity, and predictability. The results indicate that reducing legal restrictions substantially facilitates wind and solar energy capacity expansion in prioritized zones. With weak restrictions, up to 22% and 12% of Germany represent priority zones for an efficient and sustainable use of solar and wind energy. However, due to the intermittent nature of wind and solar resources, mismatches between generation potential and electricity demand would persist even with substantial capacity expansion. Future energy systems must advance the expansion of renewable energy capacities just as the flexibilization of demand or an increase of storage capacities to guarantee future energy security and mitigate climate change. The newly developed renewable energy priority zones are a starting point and can be transferred to other study areas by specifically adapting criteria and their weighting.

Model for Land Use Optimisation for Flood Management in Lasolo Watershed, Indonesia

Changes in land use from vegetation to non-vegetation in the Lasoso watershed contribute to an increase in the run-off coefficient caused by inundation during the wet season. Therefore, engineering is required to reduce discharge from surfaces. This study seeks to optimize land use in order to manage flooding. This study employs the paimin (modified) method with three different scenarios: Business as usual (BAU), simultaneous, and discrete. Results indicated that the BAU scenario has throughfall and retention capacity values of 15.55 percent and 19.39 percent of the total watershed area, respectively. scenario-2 (simultaneous) decreased throughfall and increased storage capacity (15.35 and 24.65%, respectively); scenario-3 (discrete) also improved. Comparing throughfall values reveals that the discrete simulation (-0.0020) is greater than the simultaneous scenario (-0.008), whereas the retention capacity has the same value (0.0020). The discrete simulation is superior to the simultaneous simulation in terms of optimizing its use for flood management in the Lasolo catchment.

CAES-SC hybrid energy storage: Dynamic characteristics and control via discharge process

Energy storage is an effective means to increase renewable energy utilization. Compressed air energy storage (CAES) and super-capacitor (SC) hybrid energy storage system is one of the potential options for renewable energy microgrids due to its low-cost and flexible response capacity. In this paper, we thoroughly investigate the dynamical characteristics of the CAES system and the dynamical interactions between different subsystems in the CAES-SC hybrid energy storage via the discharge process. Dynamical models have been developed for the CAES discharge subsystem and the SC subsystem. Studies of the start-up process of CAES discharge subsystems have shown that the no-load start-up mode is more efficient than the variable-load start-up mode if the equivalent power generation for the same compressed air mass consumption is measured. In terms of the interaction characteristics between the CAES subsystem and the SC subsystem, the capacity demand of the SC subsystem in the no-load start-up mode is about 8 % higher than that in the variable-load start-up mode. An optimal control strategy based on the constraint of source-load dynamic balance has also been proposed to achieve power allocation in a CAES-SC hybrid energy storage system. Case studies show that the cycle efficiency of the hybrid energy storage system corresponding to the proposed optimal control strategy is 57.91 %, which is 1.84 % higher than that of the conventional control strategy. Moreover, compared with the conventional design that takes twice the maximum energy storage capacity demand during the starting process of the CAES discharge subsystem (about 1.6 MWh), a higher designed energy storage capacity (about 3 MWh) of the SC subsystem is required to satisfy the complete response to the source-load deviation under the proposed optimal control strategy. Moreover, for every 0.5 MWh increase in the energy storage capacity of the SC subsystem, the cycle efficiency of the hybrid energy storage system can be increased by approximately 0.3 % to 0.5 %.

Microwave-absorbing performance of FeCoNi magnetic nanopowders synthesized by electrical explosion of wires

This study demonstrates fabrication of FeCoNi magnetic nanoparticles by joint electrical explosion of wires for electromagnetic wave absorption applications. An increase in the energy storage capacity of the capacitors can increase the maximum reflection loss of the nanoparticles and shift the corresponding frequency in the low-frequency direction, but has no significant effects on the maximum bandwidth. The minimum reflection loss of the magnetic nanoparticles reaches − 50.2 dB at 6.8 GHz when the thickness is 2.5 mm, while the maximum effective absorption bandwidth reaches 8.1 GHz at a thickness of 1.5 mm. The wire explosion method, as an instantaneous synthesis method with a low cost, environmental friendliness, and high-output characteristics, provides a new approach to industrial batch preparation of microwave-absorbing materials.

Multilevel optoelectronic hybrid memory based on N-doped Ge2Sb2Te5 film with low resistance drift and ultrafast speed

Multilevel phase-change memory is an attractive technology to increase storage capacity and density owing to its high-speed, scalable and non-volatile characteristics. However, the contradiction between thermal stability and operation speed is one of key factors to restrain the development of phase-change memory. Here, N-doped Ge2Sb2Te5-based optoelectronic hybrid memory is proposed to simultaneously implement high thermal stability and ultrafast operation speed. The picosecond laser is adopted to write/erase information based on reversible phase transition characteristics whereas the resistance is detected to perform information readout. Results show that when N content is 27.4 at.%, N-doped Ge2Sb2Te5 film possesses high ten-year data retention temperature of 175 °C and low resistance drift coefficient of 0.00024 at 85 °C, 0.00170 at 120 °C, and 0.00249 at 150 °C, respectively, owing to the formation of Ge–N, Sb–N, and Te–N bonds. The SET/RESET operation speeds of the film reach 520 ps/13 ps. In parallel, the reversible switching cycle of the corresponding device is realized with the resistance ratio of three orders of magnitude. Four-level reversible resistance states induced by various crystallization degrees are also obtained together with low resistance drift coefficients. Therefore, the N-doped Ge2Sb2Te5 thin film is a promising phase-change material for ultrafast multilevel optoelectronic hybrid storage.

Microencapsulation of Phase Change Materials with a Soy Oil-Based Polyurethane Shell via Pickering Emulsion Polymerization

Phase change materials (PCMs) have been widely investigated for their ability to store enormous amounts of heat while maintaining ambient temperature during phase transition. In this study, microencapsulation PCMs (MEPCMs) were synthesized using the Pickering emulsion method to address PCMs’ defects, such as severe leakage during phase transition. In this paper, modified SiO2 nanoparticles are used as emulsion stabilizers, and a polyurethane (PU) shell prepared from biobased soy polyols is used to encapsulate PCM ethyl palmitate for the successful fabrication of microcapsules. According to the findings, when the dosage of modified SiO2 nanoparticles reached 0.5 wt %, the morphologies and mechanical performance of microcapsules reached their optimal condition. Meanwhile, M-SiO2-doped microcapsules have greater thermal stability than pure ethyl palmitate. Differential scanning calorimetry (DSC) analysis indicates that when the core–shell ratio grows, the MEPCMs’ heat storage capacity increases. The latent heat of MEPCMs reached 118.5 J/g as the core–shell ratio reached 2:1. Additionally, a higher core–shell ratio could help alleviate the supercooling phenomenon of microencapsulation PCMs (MEPCMs). Moreover, the MEPCMs’ energy storage efficiency can reach 93.3% after 50 cycles of heat and cold, demonstrating that they have excellent cycle stability.

Progresses and Perspectives of All‐Iron Aqueous Redox Flow Batteries

AbstractRedox flow batteries (RFBs) are a promising option for long‐duration energy storage (LDES) due to their stability, scalability, and potential reversibility. However, solid‐state and non‐aqueous flow batteries have low safety and low conductivity, while aqueous systems using vanadium and zinc are expensive and have low power and energy densities, limiting their industrial application. An approach to lower capital cost and improve scalability is to utilize cheap Earth‐abundant metals such as iron (Fe). Nevertheless, all‐iron RFBs have many complications, involving voltage loss from ohmic resistance, side reactions such as hydrogen evolution, oxidation, and most significantly electrode plating, and dendrite growth. To address these issues, researchers have begun to examine the effects of various alterations to all‐iron RFBs, such as adding organic ligands to form Fe complexes and using a slurry electrode instead of common materials such as graphite or platinum rods. Overall, progress in improving aqueous all‐iron RFBs is at its infant stage, and new strategies must be introduced, such as the utilization of nanoparticles, which can limit dendrite growth while increasing storage capacity. This review provides an in‐depth overview of current research and offers perspectives on how to design the next generation of all‐iron aqueous RFBs.

The role of electricity market design for energy storage in cost-efficient decarbonization

The role of electricity market design for energy storage in cost-efficient decarbonization

Experimental investigation in the selection of phase change materials based on thermal stratification effect in thermal energy storage system

AbstractThis study aims to evaluate the effects of thermal stratification on thermal energy storage (TES) systems during the charging process and choose suitable phase change materials (PCMs) for various layers. The research revealed that fiberglass insulation of 60 mm thick significantly decreased natural convection losses and increased the TES system's potential for energy recovery. For constant heat load, the charging time increased with increasing HTF inlet temperature, but remained constant for the first TES layer at a specified flow rate, resulting in increased storage capacity with minimal heat loss to the surroundings. The solar collector efficiency was shown to be dependent on solar radiation and collector efficiency, with peak efficiency seen at specified periods. The lowest melting point of PCMs at each layer 68°C, 62.7°C, 57°C, and 50°C was chosen based on temperature graphs. For comparing stratification behavior, the “MIX” number versus non‐dimensional charging time plot was effective. Additional experiments are needed to assess the selected PCMs' charging and discharging properties.

Usulan Perbaikan Tata Letak Gudang Pendingin yang Memaksimalkan Daya Tampung dan Meminimumkan Rata-Rata Jarak Perpindahan (Studi Kasus PT. XYZ)

PT. XYZ's Cold Storage that is located in the Pelabuhan Perikanan Samudera Nizam Zachman Jakarta currently does not implement a storage layout system, the are randomly placed, even an empty area near the door is not utilized to put the commodity to be stored. Causing the forklift mileage to grow larger. In addition, the demand for cold storage is increasing from year to year so that cold storage should be increased current capacity, cold storage is currently able to accommodate 575 pallets. The increase in cold storage capacity is done by combining the storage flow, pallet laying position, as well as the layout method of class based storage, dedicated storage, and random storage. The combination of these three factors resulted in 18 possible proposals for the improvement of the cold storage layout. From the 18th combinations likely to be taken one combination of layouts by considering three criteria i.e. maximum capacity, minimum distance, and maximum revenue gained from maximum capacity. Proposal layout with a combination of pallet widened position, simple straight groove, with dedicated storage method to be the best proposal with a maximum capacity of 750 pallets, the minimum distance of 5728.82 m, and the company can earn a maximum income of Rp 297 million per month with the capacity.